Level with magnetic coupling

ABSTRACT

A tool, such as a level, including one or more magnetic coupling device is provided. The magnetic coupling device may be a magnetic circuit including metal components surrounding a magnet, such as a permanent rare-earth magnet.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application is a continuation of application Ser. No. 16/399,433,now U.S. Pat. No. 11,054,257, filed Apr. 30, 2019, which is acontinuation of Ser. No. 15/271,045, now U.S. Pat. No. 10,317,209, filedSep. 20, 2016, which is a continuation of International Application No.PCT/US2016/052475, filed on Sep. 19, 2016, which claims the benefit ofand priority to U.S. Provisional Application No. 62/221,257, filed onSep. 21, 2015, and U.S. Provisional Application No. 62/293,595, filed onFeb. 10, 2016, which are incorporated herein by reference in theirentireties.

BACKGROUND OF THE INVENTION

The present invention relates generally to the field of tools. Thepresent invention relates specifically to a tool, such as a level, aspirit level, a billet torpedo type level, a block torpedo type level,etc., with one or more magnetic components configured to couple thelevel to a magnetic structure or workpiece. Levels, such as spiritlevels, are used to determine the levelness of a structure, surface orworkpiece. In use the level is placed on or in contact with a surface tobe measured, and the user views the location of a bubble within a vialrelative to markings that indicate the levelness of the structure,surface or workpiece.

SUMMARY OF THE INVENTION

One embodiment of the disclosure relates to a tool, specifically alevel, including a magnetic coupling element located to direct amagnetic coupling field through or beyond a surface of the tool. Invarious embodiments, the tool is a level and the surface is a planarbase surface of the level configured to engage a surface of a workpiece.

In various embodiments, the level includes a level body formed from afirst metal material, and the magnetic coupling element is a magneticcircuit including a magnet located adjacent to at least one metallicstructure that is formed from a second metal material that is differentfrom the first metal material. In various embodiments, the magnet of themagnetic circuit is located between a pair of metallic structures andthe magnetic circuit is coupled to the level body. In some suchembodiments, each of the metallic structures includes an outward facingsurface that engages an interior surface of the level body and an inwardfacing surface that engages an outer surface of the magnet. In some suchembodiments, the engagement between the surfaces of the level body andthe metallic structures form a press fit that holds the magnetic circuitwithin the level body. In some such embodiments, at least portions ofthe surfaces of the level body and the metallic structures that form apress fit are vertical surfaces.

In various embodiments, a height of the magnet is less than the heightof the at least one metallic structure such that the magnet is recessedbelow the at least one metallic structure within the level body. Invarious embodiments, the at least one metallic structure is formed fromsteel and the magnet is a rare-earth magnet.

In various embodiments, an outer surface of the magnet and an outersurface of the at least one metallic structure are shaped to engage andinterlock with each other. In various embodiments, an outer lateralsurface of the magnet is a non-vertical surface and an outer lateralsurface of the at least one metallic structure is a non-vertical surfacethat engage each other. In various embodiments, the outer lateralsurface of the magnet is an angled surface, and the magnet includes anupper surface. In such embodiments, a maximum width of the angledsurface of the magnet is greater than a maximum width of the uppersurface.

In various embodiments, the level includes more than one discretemagnetic circuit spaced along or relative to a planar base surface. Invarious embodiments, the magnetic circuit is elongated such that themagnetic circuit extends at least 30% of the longitudinal length of thelevel. In various embodiments, the level may include an elongate grooveor channel formed in the body, and the magnetic circuit is located inthe elongate groove or channel. In various embodiments, the magnet has anorth-south axis that is substantially parallel to the planar basesurface. In some such embodiments, the north-south axis of the magnet issubstantially parallel to the longitudinal axis of the level body, andin other embodiments, the north-south axis of the magnet issubstantially parallel to the width axis of the level body.

Another embodiment of the disclosure relates to a level. The levelincludes a level body formed from a first metallic material, and thelevel body defines a base surface configured to engage a workpiece. Thelevel includes at least one level vial located within the level body anda cavity located in the level body defining an opening along the basesurface. The level includes a magnetic circuit coupled to the level bodywithin the cavity. The magnetic circuit includes a pair of metallicstructures formed from a second metallic material. The second metallicmaterial is a ferromagnetic material and is different from the firstmetallic material. The magnetic circuit includes a permanent magnetlocated between opposing inner surfaces of the pair of metallicstructures.

Another embodiment of the disclosure relates to a leveling deviceconfigured to measure levelness of a workpiece. The leveling deviceincludes a level body having a planar base surface and defines alongitudinal axis. The leveling device includes at least one level viallocated within the level body. The leveling device includes a magneticcoupling element supported by the level body such that a magnetic fieldgenerated by the magnetic coupling element extends outward from the basesurface, and the magnetic coupling element has north-south axis. Themagnetic coupling element is positioned relative to the level body suchthat the north-south axis is positioned substantially parallel to theplanar base surface and substantially perpendicular the longitudinalaxis.

Another embodiment of the disclosure relates to a tool including a toolbody formed from a first material and having a first surface. The toolincluding a magnetic coupling element supported by the tool body suchthat a magnetic field generated by the magnetic coupling element extendsoutward from the first surface. The magnetic coupling element includes apermanent magnet and a metallic sleeve structure at least partiallysurrounding the permanent magnet. The metallic sleeve structure isformed from a magnetic material that is different from the firstmaterial and has a magnetic reluctance that is less than a magneticreluctance of the first material.

Additional features and advantages will be set forth in the detaileddescription which follows, and in part will be readily apparent to thoseskilled in the art from the description or recognized by practicing theembodiments as described in the written description and claims hereof,as well as the appended drawings. It is to be understood that both theforegoing general description and the following detailed description areexemplary.

The accompanying drawings are included to provide a furtherunderstanding and are incorporated in and constitute a part of thisspecification. The drawings illustrate one or more embodiments andtogether with the description serve to explain principles and operationof the various embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a level, according to an exemplaryembodiment.

FIG. 2 is a schematic cross-sectional view of the level of FIG. 1 ,according to an exemplary embodiment.

FIG. 3 is a schematic cross-sectional view showing the magnetic field ofa magnetic circuit, according to an exemplary embodiment.

FIG. 4 is a side view of the level of FIG. 1 , according to an exemplaryembodiment.

FIG. 5 is a top view of the level of FIG. 1 , according to an exemplaryembodiment.

FIG. 6 is a side view of a magnetic circuit sleeve, according to anexemplary embodiment.

FIG. 7 is a top view of a magnetic circuit sleeve, according to anexemplary embodiment.

FIG. 8 is a perspective view of a level, according to another exemplaryembodiment.

FIG. 9 is a perspective view of a level, according to another exemplaryembodiment.

FIG. 10 is a perspective view of a level, according to another exemplaryembodiment.

FIG. 11 is a schematic view of a magnetic circuit, according to anotherexemplary embodiment.

FIG. 12 is a perspective view of a level, according to another exemplaryembodiment.

FIG. 13 is a schematic cross-section view showing the magnetic field ofa magnetic circuit, according to another exemplary embodiment.

FIG. 14 is a side view of a level, according to another exemplaryembodiment.

FIG. 15 is a perspective view of a magnetic circuit, according toanother exemplary embodiment.

FIG. 16 is a side view of a magnet of the magnetic circuit of FIG. 15 ,according to an exemplary embodiment.

FIG. 17 is a side view of a metallic sleeve of the magnetic circuit ofFIG. 15 , according to an exemplary embodiment.

FIG. 18 is a perspective view of a portion of a level including a recessfor receiving a magnetic circuit, according to an exemplary embodiment.

FIG. 19 is a side cross-sectional view of the level recess of FIG. 18 ,according to an exemplary embodiment.

FIG. 20 is a perspective view of the magnetic circuit of FIG. 15 mountedin the recess of FIG. 18 , according to an exemplary embodiment.

FIG. 21 shows insertion of the magnetic circuit of FIG. 15 into therecess of FIG. 18 , according to an exemplary embodiment.

FIG. 22 is a perspective view of a magnetic circuit, according toanother exemplary embodiment.

FIG. 23 is a detailed view of the magnetic circuit of the level of FIG.22 located within a level body, according to an exemplary embodiment.

FIG. 24 is a detailed cross-sectional of the magnetic circuit shown inFIG. 23 , according to an exemplary embodiment.

DETAILED DESCRIPTION

Referring generally to the figures, various embodiments of a level areshown. In general, the levels discussed herein include one or more levelvials and a level base. As will be generally understood, the base of thelevel is placed on a workpiece (e.g., a structure, surface, etc.) inorder for the user of the level to measure the levelness of a surface ofa structure. The level embodiments discussed herein include one or moremagnetic coupling elements located along the base that facilitateattachment, via magnetic attraction, of the level to the magnetic (e.g.,a ferromagnetic) workpiece. In various embodiments discussed herein, thelevel includes a magnetic coupling arrangement that increases themagnetic coupling force generated by the magnetic coupling element. Forexample, in some embodiments, the north-south axis of the magnet of themagnetic coupling element is aligned relative to the level base surfaceand/or to the magnetic workpiece (e.g., parallel to workpiece surfaceand/or level base) to increase the level of magnetic coupling force.

In addition, in specific embodiments, one or more of the magneticcoupling elements are formed as a magnetic circuit in which a permanentmagnet is located between or is surrounded by components (e.g., steel oriron sleeves) formed from a material having low magnetic reluctance. Aswill be understood, the low reluctance material of the magnetic circuitacts to focus/guide the magnetic field generated by the permanent magnettoward the workpiece and thereby increases the amount of magneticcoupling force generated by the permanent magnet. Applicant believesthat by utilizing the magnetic circuits and/or permanent magnetorientations discussed herein, the amount of magnetic coupling forcegenerated by a permanent magnet of particular size and material isincreased.

In addition, Applicant has found that some permanent magnet materials(e.g., rare-earth magnet materials) tend to be brittle, resulting incracking, crumbling, etc., during certain assembly processes. In atleast some embodiments, the magnetic circuit arrangements discussedherein facilitate assembly of the magnetic circuit into the level bodyby providing one or more engagement surfaces spaced from the permanentmagnet which may be contacted during assembly. In such embodiments, asthe magnetic circuit is seated within the level body, the forcenecessary to press the magnetic circuit into the level body may beapplied by the engagement surface such that direct contact with thepermanent magnet during seating can be avoided. In specific embodiments,the engagement surface may be a surface of one of the metal sleeves ofthe magnetic circuit. As such, in some embodiments, the magnetic circuitarrangements discussed herein limit the need for direct contact with thepermanent magnet component during assembly, which in turn limits therisk of damaging the permanent magnet.

Referring to FIG. 1 , a leveling device, shown as level 10, is shownaccording to an exemplary embodiment. In general, level 10 includes abody 12 that includes a base surface 14 and an opposing surface 16. Aswill be explained in more detail below, base surface 14 is a flat,planar surface that engages a surface of a workpiece to be measuredusing level 10. In at least some embodiments, body 12 is formed from anextruded metal material (e.g., extruded aluminum). In some specificembodiments, base surface 14 is machined to have a flat, flush or planarsurface following extrusion, and in some embodiments, this machinedsurfaced may be anodized.

Level 10 includes a plurality of through bores formed through body 12.As shown in FIG. 1 , level 10 includes an enlarged opening 18, a firstvial receiving opening 20 and a second vial receiving opening 22. Level10 includes a recess 24 located adjacent base surface 14. As will beunderstood, openings 20 and 22 and recess 24 receive three standardlevel vials (e.g., bubble vials) which are held in the appropriateorientation relative to base surface 14 in order for the vials toindicate the levelness of the corresponding surface of a workpiece. Invarious embodiments, enlarged opening 18 receives a large level vial. Inother embodiments, enlarged opening 18 may provide a hand hold. As shownin FIG. 1 , body 12 of level 10 generally defines a longitudinal axis26, a width axis 28 and a height axis 30. Openings 18, 20 and 22 eachdefine an axis extending between the left and right sides of level 10such that openings 18, 20 and 22 are substantially perpendicular tolongitudinal axis 26. In the specific embodiment shown, level 10 is abillet torpedo level.

Level 10 includes one or more magnetic coupling elements, shown asmagnetic circuits 32, 34 and 36. In general, magnetic circuits 32, 34and 36 generate a magnetic coupling force that allows level 10 to beattached to and held in place to a surface of a magnetic workpiece. Inthe embodiment shown in FIG. 1 , level 10 includes three discretemagnetic circuits spaced along base surface 14. In other embodiments,level 10 may include other numbers of magnetic circuits (e.g., 1, 2, 4,5, 6, etc.). Further, in the embodiment shown, each of magnetic circuits32, 34 and 36 has the same structure as each other, but in otherembodiments, the structure of one or more magnetic circuits may bedifferent from the others.

Referring to FIG. 1 and FIG. 2 , details of magnetic circuits 32, 34 and36 are explained herein, in reference to central magnetic circuit 34,with the understanding that the other magnetic circuits 32 and 36 areformed in substantially the same manner and configured in the samemanner as central magnetic circuit 34. Central magnetic circuit 34includes a pair of metallic structures, posts, blocks or sleeves, shownas left sleeve 40 and right sleeve 42, located on either side ofpermanent magnet 44.

Referring to FIG. 2 and FIG. 3 , in operation, level 10, includingmagnetic circuits 32, 34 and 36, may be coupled or attracted to magneticworkpiece 46 (e.g., a pipe) via the magnetic field generated by magnet44. FIG. 3 is a schematic diagram showing the operation of a magneticcircuit, such as circuit 34, according to an exemplary embodiment. Invarious embodiments, because sleeves 40 and 42 are formed from a lowreluctance material (e.g., steel), sleeves 40 and 42 act to guide/focusthe magnetic field generated by magnet 44 into workpiece 46 as shown inFIG. 3 . By placing the low reluctance material of sleeves 40 and 42 inclose proximity/contact with magnet 44, the magnetic field of magnet 44is channeled through sleeves 40 and 42 in a way that increases themagnetic coupling force generated by a magnet 44 given a particularmagnet size, weight, material type, etc. This is represented by theincreased density of the magnetic flux lines shown in FIG. 3 .

Further, by utilizing the magnetic circuit arrangements discussedherein, the amount of magnetic material needed to form magnet 44 toachieve a certain level of magnetic coupling force (e.g., greater than 8lbs., greater than or equal to 10 lbs., etc.) may be decreased relativeto a magnet arrangement that does not utilize sleeves 40 and 42. As willbe understood, the thickness of sleeves 40 and 42 is selected to be lowenough that the sleeves do not reach saturation, but instead guide themagnetic field as shown in FIG. 3 . In particular embodiments, thethickness and/or shape of sleeves 40 and 42 is selected to densify themagnetic flux (which increases magnetic coupling force at base surface14) emanating from the magnetic circuits away from base surface 14 givena magnet of a particular size, shape, material type, etc. In some suchembodiments, the thickness and/or shape of sleeves 40 and 42 achievesthe desired magnetic properties while also reducing or minimizing theamount of steel material needed to form sleeves 40 and 42.

In addition, Applicant has found that by positioning the north-southaxis of magnet 44 relative to base surface 14, workpiece 46, and/or thewidth axis 28 of level 10, magnetic coupling force can be controlled,selected, increased etc. relative to at least some other north-southaxis alignments. For example, as shown in FIG. 2 and FIG. 3 , in variousembodiments, the north-south axis of magnet 44 is substantially parallel(e.g., within plus or minus 10 degrees of parallel) to base surface 14,and in a specific embodiment, the north-south axis of magnet 44 issubstantially parallel (e.g., within plus or minus 10 degrees ofparallel) to base surface 14 and is also perpendicular to longitudinalaxis 26 of level 10. In other embodiments, magnetic circuit 34 may bepositioned such that that the north-south axis of magnet 44 is parallelto base surface 14 and is also parallel to longitudinal axis 26 of level10. In a specific embodiment, the north-south axis of magnet 44 iswithin plus or minus 1 degree of parallel to base surface 14.

In other embodiments, the north-south axis of magnet 44 is notperpendicular to base surface 14 and/or workpiece 46. In variousembodiments, in the plan views shown in FIG. 2 and FIG. 3 , the anglebetween the north-south axis of magnet 44 and width axis 28 is greaterthan or equal to 0 degrees and is less than or equal to 45 degrees,specifically is greater than or equal to 0 degrees and is less than orequal to 30 degrees, and more specifically is greater than or equal to 0degrees and is less than or equal to 10 degrees.

In specific embodiments, Applicant has found that the north-south axispositioning in combination with the sleeve arrangement discussed hereinprovides for improved magnetic coupling to workpiece 46 (at leastcompared to some other magnet arrangements). In specific embodiments,the north-south axis of magnet 44 is substantially perpendicular to avertical axis of sleeves 40 and 42. In such embodiments, thisarrangement increases the portion of the magnetic field of magnet 44that is allowed to interact with sleeves 40 and 42, which in turnimproves the ability of sleeves to guide/focus the magnetic field.

Without wishing to be bound by a particular theory, Applicant believesthat the function of the magnetic circuit arrangements discussed hereincan be understood as follows. High reluctance material can be thought ofas “less magnetic” material, such as plastic, aluminum or air. In a highreluctance material, magnetic energy is stored. Low reluctance materialsare materials that are more magnetic, like metals, such as steel.Further, the flux paths of a magnet generally flow from the north poleof the magnet to the south pole of the magnet. As shown in FIG. 3 , theflux paths pass from the north pole of magnet 44 through sleeve 40, intoworkpiece 46, back into sleeve 42 and into the south pole of magnet 44.In this arrangement, there is little or no high reluctance material(e.g., plastic, aluminum or air) along the flux paths from the magnetand into the workpiece, and thus all or substantially all of themagnetic field of magnet 44 is available for coupling to the workpiecerather than being stored within a high reluctance material.

Referring to FIG. 2 , in various embodiments, level body 12 isconfigured to receive and hold the magnetic circuits of level 10. Forexample, sleeves 40 and 42 and magnet 44 are located within a cavity, orrecess 48, formed in body 12. In this arrangement, lower surfaces ofsleeves 40 and 42 and of magnet 44 are seated against a lower, upwardfacing surface of recess 48. In addition, the left side surface ofsleeve 40 abuts and contacts the inward facing left surface of recess48, and the right side surface of sleeve 40 abuts and contacts theoutward facing left surface of magnet 44. Similarly on the opposite sideof magnetic circuit 34, the right side surface of sleeve 42 abuts andcontacts the inward facing right surface of recess 48, and the left sidesurface of sleeve 42 abuts and contacts the outward facing right surfaceof magnet 44. In some embodiments, body 12 is formed from a metal (e.g.,aluminum) that is different from the metal material of sleeves 40 and 42(e.g., steel), which are both different from the material of magnet 44(e.g., a rare-earth magnet). In such embodiments, each of the interfacesdiscussed above represents an interface between different materialtypes.

In some embodiments, magnetic circuits of level 10 are press fit intothe corresponding receiving cavities (e.g., recess 48) within level body12. In such embodiments, frictional forces between the outer surfaces ofsleeves 40 and 42 and the inner surfaces of recess 48 act to holdmagnetic circuit 34 into recess 48. In some such embodiments, adhesiveor glue material is not included within recess 48 to hold magneticcircuit 34 in place. In some other embodiments, an adhesive material islocated within recess 48 to hold magnetic circuit 34 in place.

Referring to FIG. 2 , the magnetic circuits of level 10, such as circuit34, are further configured to facilitate mounting of magnetic circuit 34within recess 48 while protecting magnet 44 from damage duringinstallation. In such embodiments, magnet 44 is sized such that magnet44 is recessed below the outer most surfaces of sleeves 40 and 42 in thevertical direction. In this embodiment, an offset distance is locatedbetween the upper most surface of magnet 44 and the upper most surfacesof sleeves 40 and 42. In various embodiments, the offset distance isbetween 0 and 0.5 inches, and in another embodiment, the offset distanceis between 0 and 1 inches. In at least some embodiments, the offsetdistance allows a downwardly directed vertical force to be applied tothe upper surfaces of sleeves 40 and 42 during the step of press fittingmagnetic circuit 34 into recess 48. This arrangement limits oreliminates contact with magnet 44 as magnetic circuit 34 is pressed intolevel 10. In particular embodiments, magnet 44 is formed from arare-earth magnetic material that tends to be brittle, and the offsetallows press fitting of magnetic circuit 34 while protecting magnet 44from damage that may otherwise occur as a result of application of theforces during press fitting.

As shown in FIG. 2 , sleeves 40 and 42 are also recessed below basesurface 14 adjacent recess 48, creating an air gap G between upper mostsurfaces of sleeves 40 and 42 and the opposing surface of the workpiece46. In various embodiments, the relative sizes of sleeves 40 and 42 andrecess 48 are selected so that the height of air gap G is relativelysmall to improve/increase the amount of coupling force generated bymagnetic circuit 34. In various embodiments the height of air gap G isless than 0.01 inches. In some embodiments, the relative sizes ofsleeves 40 and 42 and recess 48 are selected so that the height of airgap G is greater than or equal to zero and less than or equal to 0.01inches, and in a specific embodiment, air gap G is zero such that theupper surfaces of sleeves 40 and 42 are coplanar with base surface 14.In addition, as shown in FIG. 2 , magnetic circuit 34 is uncovered(e.g., by a portion of level body 12) such that the outermost surfaces(shown as the upper surfaces in the orientation of FIG. 2 ) of themagnetic circuit 34 define a portion of the outermost surface of level10 at the location of recess 48.

In various embodiments, sleeves 40 and 42, magnet 44 and recess 48 maybe shaped and sized in various ways as desired to achieve variousmagnetic field properties and/or to accommodate various level designs.Referring to FIGS. 4-7 , various sizes of recess 48 and of sleeve 40 areshown, with the understanding that the other recesses of level 10 arethe same as recess 48 and that the sleeve 42 is the same as sleeve 40.

As shown in FIG. 4 , recess 48 has a height, H1, a length, L1 and awidth, W1. In various embodiments, H1 is between 0.1 and 0.4 inches,specifically between 0.2 and 0.3 inches and more specifically about 0.26inches (e.g., 0.26 inches plus or minus 0.005 inches). In variousembodiments, L1 is between 0.2 and 0.6 inches, specifically between 0.3and 0.4 inches and more specifically about 0.38 inches (e.g., 0.38inches plus or minus 0.001 inches). In various embodiments, W1 isbetween 0.2 and 0.7 inches, specifically between 0.4 and 0.5 inches andmore specifically about 0.43 inches (e.g., 0.43 inches plus or minus0.005 inches). In specific embodiments, recess 48 has a volume that isbetween 0.01 inches³ and 0.1 inches³, specifically between 0.035 inches³and 0.05 inches³, and more specifically between 0.04 inches³ and 0.045inches³. In a specific embodiment, recess 48 has a volume of about0.0425 inches³. Applicant believes that recesses, as described herein,provide a combination of functionality including sufficient size tocontain magnet 44 and sleeves 40 and 42, while also providing sufficientbody support to provide press fit friction within level body 12.

Referring to FIG. 6 and FIG. 7 , detailed views of sleeve 40 are shownaccording to an exemplary embodiment. FIG. 6 shows a side elevationview, and in this embodiment, sleeve 40 includes a height, H2, and alength, L2, and as shown in FIG. 7 , includes a width, W2. In variousembodiments, H2 is between 0.1 and 0.4 inches, specifically between 0.2and 0.3 inches and more specifically about 0.25 inches (e.g., 0.25inches plus or minus 0.005 inches). In a specific embodiment, H2 is lessthan H1 such that the sleeves are slightly recessed below base surface14, resulting in air gap G between sleeves 40 and 42 and workpiece 46(show in FIG. 2 ). In specific embodiments, H2 is between 0.005 and 0.02inches less than H1. In various embodiments, L2 is between 0.2 and 0.6inches, specifically between 0.3 and 0.4 inches and more specificallyabout 0.385 inches (e.g., 0.385 inches plus or minus 0.001 inches). Inspecific embodiments, L2 is slightly larger than L1 such that a pressfit is formed between the sleeves and the inner surfaces of thecorresponding recess. In general, W2 is selected such that both sleeves(e.g., sleeves 40 and 42) and magnet 44 fit widthwise within recess 48.

In general, magnet 44 is sized and shaped to fit within recess 48,between sleeves 40 and 42. In general, the dimensions, volume, weight,etc. of magnet 44 are selected such that magnetic circuit 34 providesthe desired level of magnetic coupling force. In various embodiments, asshown best in FIG. 1 and FIG. 2 , magnet 44 has a height, H3, a width,W3 and a length, L3. In various embodiments, H3 is between 0.1 and 0.4inches, specifically between 0.2 and 0.3 inches and more specificallyabout 0.25 inches (e.g., 0.25 inches plus or minus 0.001 inches). Asnoted above, in specific embodiments H3 is less than H2 such that magnet44 is recessed below adjacent sleeves 40 and 42, and in specificembodiments, the difference between H3 and H2 is between 0.001 and 0.01inches. In various embodiments, L3 is between 0.2 and 0.6 inches,specifically between 0.3 and 0.4 inches and more specifically about 0.38inches (e.g., 0.38 inches plus or minus 0.001 inches). In specificembodiments, L3 is slightly less than both L1 and L2 such that the frontand rear vertical surfaces of magnet 44 do not engage with the verticalsurfaces of recess 48 upon press fit, and in a specific embodiment, thedifference between L3 and L2 is less than 0.005 inches.

In various embodiments, W1 is between 0.05 and 0.2 inches, specificallybetween 0.1 and 0.2 inches and more specifically about 0.13 inches(e.g., 0.13 inches plus or minus 0.005 inches). As will be understood,to form a press fit within recess 48 in the widthwise direction, the sumof the width of magnet 44, W3, and the sum of the widths of the twosleeves 40 and 42 (both W2) is slightly larger than the width W1 ofrecess 48.

As noted above, in various embodiments, magnet 44 is sized such thateach magnetic circuit generates sufficient magnet coupling force tosecure the adjacent portion of level 10 to the magnetic workpiece. Inaddition, the total magnetic coupling force generated by all of themagnetic circuits of level 10 is sufficient to secure and firmly supportlevel 10 from the magnetic workpiece in the vertical orientation (seeFIGS. 2 and 3 ) and/or in a horizontal position relative to theworkpiece. In various embodiments, each magnet 44 has a volume that isbetween 0.005 inches³ and 0.3 inches³, specifically between 0.01 inches³and 0.02 inches³, and more specifically between 0.01 inches³ and 0.015inches³. In a specific embodiment, magnet 44 has a volume of about0.01235 inches³.

In specific embodiments, the arrangement of sleeves 40 and 42 of eachmagnetic circuit allows each magnetic circuit to generate at least 8lbs., and more specifically greater than or equal to 10 lbs. of magneticcoupling force, as measured when a magnetic workpiece is in contact withbase surface 14. In various embodiments, magnet 44 having the dimensionsand/or weights discussed herein generates a magnetic field having one ormore of the following properties outside of the magnetic circuit.Applicant believes the magnetic circuit arrangements discussed hereingenerate this high level of magnetic coupling force, despite therelatively low quantities of magnetic material utilized in each circuit.

As will be understood, the total coupling force for a particular leveldesign is determined by the number of magnetic circuits, each having acoupling force as discussed herein. Thus, in various embodiments,magnetic circuits 32, 34 and 36 combined generate greater than 24 lbs.of coupling force, and specifically greater than or equal to 30 lbs. ofcoupling force.

In various embodiments, sleeves 40 and 42 and magnet 44 may be made fromany suitable material to form a magnetic circuit as discussed herein. Ingeneral, sleeves 40 and 42 can be any ferromagnetic material, such asiron, nickel, cobalt and their alloys. In a specific embodiment, sleeves40 and 42 are made from a steel material. In general, magnet 44 may beany permanent magnetic material, and in specific embodiments, magnet 44may be a rare-earth magnet, such as neodymium magnet or samarium-cobaltmagnet. In other embodiments, magnet 44 may be formed from a non-rareearth magnetic material, such as a ferrite ceramic material or analuminum nickel cobalt (alnico) alloy material.

Referring to FIGS. 8-14 , additional embodiments of levels utilizing oneor more magnetic coupling elements as discussed herein are shown. FIG. 8shows a leveling device, shown as level 60, according to an exemplaryembodiment. As shown in FIG. 8 , level 60 is substantially similar tolevel 10 except as discussed herein. Level 60 includes a longitudinalgroove 62 located adjacent base surface 14, and groove 62 facilitatescoupling level 60 to an elongate workpiece such as a pipe, conduit, etc.Groove 62 extends substantially the entire length of level 60, anddivides base surface 14 to a left section 64 and a right section 66.Similar to level 10, level 60 includes three discreet magnetic circuits32, 34 and 36. However, as shown in FIG. 8 , circuits 32, 34 and 36reside within groove 62 such that magnets 44 reside at or beneath afloor surface 68 of groove 62 and the sleeves include angled surfaces 70that substantially follow the slope of the angled sidewalls 72 of groove62.

FIG. 9 shows a leveling device, shown as level 80, according to anexemplary embodiment. As shown in FIG. 9 , level 80 is substantiallysimilar to level 10 except as discussed herein. Level 80 includes alarge or elongate magnetic coupling element, shown as magnetic circuit82. Magnetic circuit 82 has a larger footprint than circuit 32, 34 or 36along base surface 14. In this embodiment, magnetic circuit 82 includesfirst and second metal sleeves 84 and 86 positioned on either side ofmagnet 88. In various embodiments, the length and/or width of sleeves84, 86 and magnet 88 are greater than those discussed above regardingcircuits 32, 34 or 36, and in the specific embodiment shown, level 80only includes a single elongate discrete magnetic circuit 82. As shownin FIG. 9 , the elongated shape of sleeves 84 and 86 and of magnet 88are such that the longitudinal axes of each component are parallel toeach other, are parallel to the plane of base surface 14 and areparallel to the longitudinal axis of level 80.

FIGS. 10 and 11 show a leveling device, shown as level 100, according toan exemplary embodiment. As shown in FIG. 10 , level 100 issubstantially similar to level 10 except as discussed herein. Level 100includes an elongate magnetic coupling element, shown as elongatemagnetic circuit 102, located extending along base surface 14. Invarious embodiments, elongate magnetic circuit 102 extends in adirection substantially parallel to the longitudinal axis 26 of level100. In various embodiments, elongate magnetic circuit 102 extends atleast 30%, and more specifically, at least 50% of the length of level100.

Elongate magnetic circuit 102 includes an elongate left sleeve 104, anelongate right sleeve 106, and one or more magnets 108 located betweensleeves 104 and 106. In general, magnetic circuit 102 operates in amanner similar to magnetic circuit 34 discussed above, and specifically,sleeves 104 and 106 are formed from a low reluctance material that actsto focus/guide the magnetic field generated by magnets 108. As shown inFIG. 11 , in an exemplary embodiment, magnets 108 are discrete magnets(e.g., having a length of about 1 inch) that are arranged end to endlocated between sleeves 104 and 106. As shown in FIG. 10 , magneticcircuit 102 may include a pair of separate metal sections forming sleeve104, and a second pair of separate metal sections forming sleeve 106,where one section of each pair is located before the vial recess 24 andwhere one section of each pair is located after the vial recess 24.

Further, as shown in FIG. 11 , in various embodiments, magnets 108 arearranged so that the north-south axis of at least one magnet 108 isoriented in the same direction as at least one other magnet 108 ofmagnetic circuit 102, and in a specific embodiment, magnets 108 arearranged so that the north-south axis of each magnet 108 is oriented inthe same direction as all of the other magnets 108 of magnetic circuit102. In addition, magnets 108 are positioned such that the north-southaxis of magnets 108 are substantially perpendicular to longitudinal axis26 (e.g., within plus or minus 10% of perpendicular). Further, invarious embodiments, magnets 108 are positioned such that thenorth-south axis of magnets 108 are substantially parallel (e.g., withinplus or minus 10% of parallel) to base surface 14 and/or to theworkpiece surface engaged by base surface 14, and in a specificembodiment, magnets 108 are positioned such that the north-south axis ofmagnets 108 are within plus or minus 1% of parallel to base surface 14and/or to the workpiece surface engaged by base surface 14.

FIGS. 12 and 13 show a leveling device, shown as level 120, according toan exemplary embodiment. As shown in FIG. 12 , level 120 issubstantially similar to level 100, except as discussed herein. Level120 includes a longitudinal channel 122 defined within the material ofthe level body and located adjacent base surface 14. Channel 122 extendssubstantially the entire length of level 120 and divides base surface 14to a left section 124 and a right section 126, and is shaped to receivean elongate magnetic circuit 130, which is similar to elongate magneticcircuit 102 except as discussed herein.

As shown in FIG. 12 , elongate magnetic circuit 130 resides withinchannel 122 such that magnets 138 reside on top of floor surface 128 ofchannel 122, and the sleeves 134 and 136 include angled surfaces 140that angle outward and upward toward base surface 14. In particularembodiments, the upper surfaces of magnets 138 form a continuous orsubstantially continuous (e.g., continuous except for slight gaps at theend to end interface of magnet pieces) surface that extendssubstantially the entire length of level 120. In this arrangement,magnets 138 and the angled surfaces 140 of sleeves 134 and 136 form agenerally V-shaped groove 142 that facilitates coupling of level 120 toan elongate workpiece such as a pipe, conduit, etc. In otherembodiments, groove 142 may be any other shape as desired for aparticular application. For example, groove may be U-shaped with acurved lower surface or may be square or rectangular in shape having aflat lower surface with perpendicular sidewalls.

Referring to FIG. 13 , the guiding/focusing of the magnetic field causedby sleeves 134 and 136 is shown according to an exemplary embodiment. Inthis embodiment, sleeves 134 and 136 each include an outermost surface,144 and 146 respectively, and in various embodiments, surfaces 144 and146 are planar, flat, contact surfaces that directly engage or contactworkpiece 46. In various embodiments, the width dimension (thehorizontal dimension in FIG. 13 ) of surfaces 144 and 146 is sized toproduce the desired level of focusing/guiding of the magnetic field ofmagnet 138. In specific embodiments, the width of sleeves 134 and 136 ata lower position adjacent to magnet 138 is greater than the width atsurfaces 144 and 146, and in particular embodiments, angled surfaces 140angle upward and outward from the wider lower portion to the narrowerouter surface of sleeves 134 and 136.

FIG. 14 shows a leveling device, shown as level 160, according to anexemplary embodiment. As shown in FIG. 14 , level 160 is substantiallysimilar to level 10 except as discussed herein. Level 160 is a blocktorpedo style level, and in various embodiments, may be formed from diecast metal such as aluminum. Level 160 may include any of the featuresof any of the embodiments, including any of the magnetic circuitembodiments, discussed herein.

Referring to FIG. 15 , a magnetic circuit 170 is shown according to anexemplary embodiment. Magnetic circuit 170 is substantially the same asmagnetic circuit 34, except as discussed herein, and magnetic circuit170 may be used to provide magnetic coupling functionality in any of thevarious tools and levels discussed herein.

Magnetic circuit 170 includes a pair of metallic structures, posts,blocks or sleeves, shown as left sleeve 172 and right sleeve 174,located on either side of permanent magnet 176. In general, sleeves 172and 174 and/or magnet 176 are shaped, designed or configured to holdtogether magnetic circuit 170 and/or to facilitate mounting of magneticcircuit 170 into a level body recess, such as recess 48 discussed above.More specifically, the components of magnetic circuit 170 includecooperating interfacing surfaces that facilitate interlocking orfrictional engagement between the components of magnetic circuit 170.This engagement/interlocking may facilitate handling and mounting ofmagnetic circuit 170 into the recess in the level body and may alsofacilitate retention of the magnetic circuit 170 in the level body.

In general, the interlocking engagement between magnet 176 and sleeves172 and 174 is provided by at least one portion of magnet 176 beingsized such that it is received within or engages with sleeves 172 and174 such that relative movement between magnet 176 and sleeves 172 and174 is resisted in the direction of arrow 178 (which in at least someembodiments is the direction perpendicular to base surface 14 whenmagnetic circuit 170 is installed in a level body). The resistance ofrelative motion between magnet 176 and sleeves 172 and 174 in thedirection of arrow 178 acts to retain magnet 176 within the level bodyrecess following mounting. In particular embodiments, at least onedimension, such as a width or length dimension of magnet 176, at alocation between the opposing upper and lower surfaces, is greater thanthe corresponding dimension, such as a width or length dimension ofmagnet 176, at the upper and/or lower surfaces of the magnet. Thisstructure allows the sleeves, such as sleeves 172 and 174, to have acorresponding mating shape or recess that receives or engages the largerdimension portion of magnet 176 such that magnetic circuit 170 is heldtogether once assembled.

As shown in FIGS. 15-17 , the interlocking arrangement is provided bymagnet 176 having outer lateral surfaces 180 and 182 having a taperedshape, which interlocks with a corresponding and opposite tapered shapeof inner sleeve surfaces 184 and 186. As shown in FIGS. 15 and 16 ,outer lateral surfaces 180 and 182 each include at least one section(shown as an upper section) which is angled inward (away from sleeves172 and 174) in the direction towards upper surface 188 and a secondsection (shown as a lower section) which is angled inward (away fromsleeves 172 and 174) in the direction towards lower surface 190. Asshown in FIG. 16 , the tapered shape results in width W4 of magnet 176at surfaces 188 and at 190 being less than the width W5 at the center ofmagnet 176.

The tapered shape of lateral surfaces 180 and 182 is mirrored by taperedshape of inner sleeve surfaces 184 and 186. As shown in FIGS. 15 and 17, inner surfaces 184 and 186 are V-shaped relative to the upper andlower sleeve surfaces 192 and 194. Inner surfaces 184 and 186 eachinclude at least one section (shown as an upper section) which anglesinward (away from sleeves 172 and 174) in the direction towards uppersurface 188 of magnet 176 and a second section (shown as a lowersection) which angles inward toward (away from sleeves 172 and 174) inthe direction towards lower surface 190 of magnet 176. As shown in FIG.17 , the tapered shape results in width W6 of sleeves 172 and 174 atsurfaces 192 and at 194 being greater than the width W7 at the center ofsleeves 172 and 174. When assembled, the maximum width portion W5 ofmagnet 176 aligns with the minimum width portions W7 of sleeves 172 and174 such that the surfaces 184 and 186 of sleeves 172 and 174 extendalong and contact surfaces 180 and 182 of magnet 176.

As shown in FIG. 16 , outer lateral surfaces 180 and 182 form an angleA, relative to the plane of upper surface 188 or of lower surface 190.In various embodiments, angle A is greater than 10 degrees and less than90 degrees, specifically is between 30 and 85 degrees, and morespecifically is between 70 degrees and 80 degrees. In a specificembodiment, angle A is 75 degrees plus or minus 0.5 degrees. As shown inFIG. 17 , inner sleeve surfaces 184 and 186 form an angle B, relative tothe plane of upper surface 192 or of lower surface 194. In theembodiment shown, angle A and angle B are supplementary angles such thatthe sum of angles A and B is 180 degrees, and in some such embodiments,in order to have the angled interlocking shape neither angle A or B isequal to 90 degrees. In various embodiments, angle B is less than 170degrees and greater than 90 degrees, specifically is between 150 and 95degrees, and more specifically is between 110 degrees and 100 degrees.In a specific embodiment, angle B is 105 degrees plus or minus 0.5degrees.

As shown in FIG. 16 , the poles of magnet 176 are oriented such that themagnetic south pole is at either lateral surface 180 or 182 and themagnetic north pole is located at the other lateral surface 180 or 182.In such arrangements, the axis between the magnetic poles extendsbetween lateral surfaces 180 and 182, and in specific embodiments, isparallel to surfaces 188 and/or 190. In this arrangement, the magneticnorth and south poles are located adjacent to sleeves 172 and 174 whenassembled into magnetic circuit 170, and this arrangement results in thefocusing of the magnetic field of magnet 176 as discussed above andshown in FIG. 3 .

Thus, in the arrangement shown in FIGS. 15-17 , magnet 176 has asubstantially hexagonal shape, and sleeves 172 and 174 have v-shapedsurfaces 184 and 186 that engage opposing lateral surfaces of magnet176. However, in other embodiments, magnet 176 and sleeves 172 and 174may have a variety of other shapes that create engagement that limits orprevents relative movement as discussed herein. For example, magnet 176may have a trapezoidal shape such that the lateral surfaces taper towardupper surface 188 and such that magnet 176 has a maximum width at lowersurface 190. In other embodiments, outer lateral surfaces 180 and 182may have projections, posts, ridges, etc. that engage with cooperatingfeatures on inner lateral surfaces 184 and 186 of sleeves 172 and 174,respectively.

Referring back to FIG. 15 , the sizing of magnetic circuit 170 is shownin more detail. Magnetic circuit 170 is sized relative to a level bodyrecess, such as recess 48, to provide an interference fit holdingmagnetic circuit 170 into the level body. Magnetic circuit 170 has aheight, H4, a length, L4, and a width, W8. In various embodiments, H4 isbetween 0.2 inches and 0.3 inches and specifically is about 0.250inches. In various embodiments, L4 is between 0.25 inches and 0.35inches and specifically is about 0.300 inches. In various embodiments,W8 is between 0.4 inches and 0.5 inches and specifically is about 0.45inches.

Similar to the embodiments discussed above, magnet 176 is sized suchthat upper magnet surface 188 is recessed slightly below upper sleevesurfaces 192. To provide this recess of magnet 176, height H5, of magnet176, is less than height H6, of sleeves 172 or 174. In variousembodiments, H5 is 6.28 mm plus or minus 0.05 mm, and H6 is 6.35 mm plusor minus 0.02 mm. In specific embodiments, magnet 176 is a neodymiummagnet including a nickel plating. In specific embodiments, the platinghas a thickness between 17 and 20 micrometers. In specific embodiments,magnet 176 has a minimum pull-off force of 30 N, a residual flux density(Bs) of 3.0-3.2 Kgs, density of 7.4-7.5 g/cm³, hardness (Rockwell) 44-49HRC, min radii of 0.05 mm, max operating temperature of 80 degrees C.,Curie temp of 310 degrees C. minimum, coercive force (Hci) greater than12 KOe, and maximum energy product (BH) of 40-42 MGOEe.

In specific embodiments, sleeves 172 and 174 are formed from a material(e.g., steel) having a hardness (e.g., a Rockwell hardness) greater thanthe hardness of magnet 176. In such embodiments, the higher hardness ofsleeves 172 and 174 provides a hard, robust component for pushingequipment to apply force (such as force 214 shown in FIG. 21 ) against,as magnetic circuit 170 is mounted into the recess in the level body.Thus, in this arrangement, the installation force is applied to sleeves172 and 174 rather than directly to magnet 176 during installation. Inparticular embodiments, sleeves 172 and 174 have a hardness (Rockwell)of 50-100 HRF and specifically of 80 HRF.

Referring to FIGS. 18-21 , a level body, such as level body 12, isshaped to include a recess, such as recess 48, that includes one or morestructure that facilitates mounting and retention of magnetic circuit170 in the level body. As shown in FIG. 19 , recess 48 includes an uppersection 200 that is sized relative to magnetic circuit 170 such that asmall gap or clearance is formed between the inner surface 202 of levelbody 12 and the outer surface of magnetic circuit 170 within theclearance section. Recess 48 also includes a lower section 204 that issized relative to magnetic circuit 170 such that an interference fit isformed between inner surface 202 and the outer lateral surfaces ofmagnetic circuit 170 within the interference section. In general, lowersection 204 has at least one dimension, shown as L5, that is less thanat least one dimension of magnetic circuit 170, such that aninterference fit is formed with magnetic circuit 170. In the embodimentshown, surface 202 includes a constant diameter within clearance section200 and a constant diameter within interference section 204. In thisembodiment, a step or shoulder 216 is located between the clearancesection 200 and interference section 204. In other embodiments, surfaces202 may include at least one tapered section such that the dimension L5decreases gradually along the height of recess 48.

In particular as shown in FIG. 20 , following installation of magneticcircuit 170 into recess 48, interference fit sections 206 are formedbetween sleeves 172 and 174 and sections of inner surface 202 withininterference section 204. In particular, in this embodiment, L4 ofsleeves 172 and 174 is greater than L5 of recess 48 such that theinterference fit is formed. In particular embodiments, L4 is between0.01 mm and 0.05 mm greater than L5 such that the appropriateinterference fit is formed.

Further, as shown best in FIG. 20 , magnet 176 has a length, shown asL6, which is less than both L4 and L5, such that clearance sections 208are formed between magnet 176 and inner surface 202 of recess 48. Thissizing allows magnetic circuit 170 to be retained (at least in part) viaan interference fit with recess 48 while limiting or preventing contactbetween outer surfaces of magnet 176 and inner surface 202 of recess 48which in turn limits or prevents damage to magnet 176 during insertioninto recess 48.

Referring back to FIG. 19 , recess 48 includes a lower recess or pocket210. Pocket 210 is located at the lower end of recess 48 opposite frombase surface 14. Pocket 210 is defined by a section of inner surface 202that has a dimension shown as L7 that is less than L6, and has a heightthat is less than the height of clearance section 200 and/orinterference section 204. In various embodiments, the height of pocket210 is less than 30% of the height of recess 48, specifically less than20% of the height of recess 48, more specifically less than 10% of theheight of recess 48 and even more specifically less than 5% of theheight of recess 48. In particular embodiments, pocket 210 receives abinding agent, such as epoxy, that bonds to the lower surfaces ofsleeves 172 and 174 and/or magnet 176 to help retain magnetic circuitwithin recess 48. Thus, in such embodiments, both an interference fitand epoxy is used to hold magnetic circuit 170 within level body 12. Inanother embodiment, epoxy and no interference fit is used to holdmagnetic circuit 170 within level body 12. In another embodiment,interference fit and no epoxy is used to hold magnetic circuit 170within level body 12.

Referring to FIG. 21 , insertion of magnetic circuit 170 into recess 48is shown according to an exemplary embodiment. In an embodiment in whichepoxy is used, an epoxy material 212 is located in recess 210. Then aforce, shown as arrows 214, is applied to sleeves 172 and 174, to pushmagnetic circuit 170 into recess 48. In this manner, magnetic circuit170 is installed into recess 48 without the need to apply insertionforce directly onto magnet 176. As magnetic circuit 170 is moved intorecess 48 an interference fit is created, and the lower surface ofmagnetic circuit 170 comes into contact with epoxy 212. Epoxy 212 thencures bonding to both inner surface 202 defining recess 48 and one ormore surface of magnetic circuit 170.

FIG. 22 shows a leveling device, shown as level 220, according toanother exemplary embodiment. As shown in FIG. 22 , level 220 issubstantially similar to the levels discussed above, such as levels 10and 60, except for the difference discussed or shown in the drawings.Level 220 includes a longitudinal groove 62 located adjacent basesurface 14, and, as discussed above, groove 62 facilitates couplinglevel 220 to an elongate workpiece such as a pipe, conduit, etc. Level220 includes two, discreet magnetic circuits 222 and 224 located withingroove 62. Similar to the magnetic circuits of level 60, the outersurfaces of magnetic circuits 222 and 224 are generally shaped to followthe contours of groove 62 which facilitates engagement with the elongateworkpiece.

In the specific embodiment shown in FIG. 22 , level 220 includes ahorizontal level vial 226, a vertical level vial 228 and a rotatinglevel vial 230. In general, rotating level vial 230 is mounted such thatlevel vial 230 is positionable at a number of different angles relativeto base surface 14, as desired by the user of level 220. Level 220includes a break or lock 232, such as friction lock, that engagesrotating level vial 230 to hold or fix rotating level vial 230 in thedesired position selected by the user.

Magnetic circuits 222 and 224 are positioned along base surface 14within groove 62 to facilitate coupling of level 220 to a workpiece.Specifically, in the embodiment shown, magnetic circuit 222 is locatedbelow (e.g., along an axis perpendicular to base surface 14) at least aportion of horizontal level vial 226, and magnetic circuit 224 islocated along base surface 14 located, at least in part, betweenrotating level vial 230 and the end 234 of the level that includes lock232.

Referring to FIGS. 23 and 24 , magnetic circuit 222 is shown in moredetail. It should be understood, that while FIGS. 23 and 24 specificallyshow magnetic circuit 222, both magnetic circuits 222 and 224 have thesame configuration, in at least some embodiments. In other embodimentshowever, one of magnetic circuit 222 or 224 is formed as shown in FIGS.23 and 24, and the remaining magnetic circuit(s) are configured as oneof the other magnetic circuit designs discussed herein.

As shown in FIGS. 23 and 24 , magnetic circuit 222 includes a pair ofmetallic structures, posts, blocks or sleeves, shown as left sleeve 240and right sleeve 242, located on either side of permanent magnet 244. Inthis arrangement, magnetic circuit 222 is mounted within a recess 246formed in the body of level 220, and in a specific embodiment, anadhesive material, such as an epoxy, bonds the components of magneticcircuit 222 into recess 246. In the embodiment shown, the combinedwidths, W9, of sleeves 240 and 242 and magnet 244 are less than thelength, L8, of magnetic circuit 222, resulting in the elongated magneticcircuit shape shown in FIGS. 23 and 24 . In specific embodiments, L8 isat least twice W9 which provides level 220 with a total magnet circuitsize or total magnetic coupling force large enough to support level 220from a workpiece with two magnetic circuits. As shown in FIG. 23 , theelongated shape of sleeves 240 and 242 and of magnet 244 are such thatthe longitudinal axes of each component are parallel to each other, areparallel to the plane of base surface 14 and are parallel to thelongitudinal axis of level 220.

In addition to the elongate shape of magnetic circuit 222, magnet 244 issized relative to sleeves 240 and 242 to provide a level magnetic fieldconcentration and coupling force that securely attaches level 220 to amagnetic workpiece. As shown in FIG. 24 , the width, W10, of magnet 244is less than the widths, W11, of sleeves 240 and 242. In specificembodiments, W10 is less than 75% of W11, which Applicant has foundresults in a magnet size to magnetic circuit size that provides thedesired level of magnetic field concentration (which in turn providesthe desired level of magnetic coupling) while still maintaining arelatively small footprint on the base surface 14.

As shown best in FIG. 24 , sleeves 240 and 242 are shaped relative torecess 246 and relative to magnet 244 to provide various magneticcoupling, magnet protection and assembly advantages as discussed herein.Sleeves 240 and 242 each include angled surfaces 250 that angle inwardtoward magnet 244 at an angle that matches the angle of the surfaces ofchannel 62. In various embodiments, angled surfaces 250 are positionedat an angle B relative to the angle of the base surface 14. In variousembodiments, angle B this is between 0 degrees and 90 degrees,specifically between 10 degrees and 80 degrees and more specifically isbetween 20 degrees and 60 degrees. The height of magnet 244 is such thatmagnet is recessed a short distance below the corners 252 locatedbetween angled surfaces 250 and the inner, vertical surfaces of sleeves240 and 242. As discussed above, this recess protects magnet 244 duringlevel assembly and during use of the level by limiting direct contactbetween magnet 244 and the work piece which may crack, chip or otherwisedamage magnet 244. Angled surfaces 250 angle inward from generallyplanar horizontal surfaces 254. Horizontal surfaces 254 are generallyparallel to base surface 14 and are recessed slightly below the outer,adjacent sections of base surface 14. In uses in which level 220 is usedto measure planar surface (i.e., a surface of a workpiece that is notbeing received in channel 62), this arrangement allows base surface 14to contact the planar workpiece surface while limiting direct contactwith sleeves 240 and 242.

It should be understood that while the disclosure herein relatesprimarily to leveling tools utilizing a magnetic coupling element, themagnetic coupling element embodiments discussed herein may beincorporated into a wide variety of tools that may benefit from magneticcoupling. In various embodiments, the magnetic circuits discussed hereinmay be utilized in screw drivers and other hand tools, protractors,combination squares, magnetic cleaning tools, sweeps, clubs, etc.

It should be understood that the figures illustrate the exemplaryembodiments in detail, and it should be understood that the presentapplication is not limited to the details or methodology set forth inthe description or illustrated in the figures. It should also beunderstood that the terminology is for the purpose of description onlyand should not be regarded as limiting.

Further modifications and alternative embodiments of various aspects ofthe invention will be apparent to those skilled in the art in view ofthis description. Accordingly, this description is to be construed asillustrative only. The construction and arrangements, shown in thevarious exemplary embodiments, are illustrative only. Although only afew embodiments have been described in detail in this disclosure, manymodifications are possible (e.g., variations in sizes, dimensions,structures, shapes and proportions of the various elements, values ofparameters, mounting arrangements, use of materials, colors,orientations, etc.) without materially departing from the novelteachings and advantages of the subject matter described herein. Someelements shown as integrally formed may be constructed of multiple partsor elements, the position of elements may be reversed or otherwisevaried, and the nature or number of discrete elements or positions maybe altered or varied. The order or sequence of any process, logicalalgorithm, or method steps may be varied or re-sequenced according toalternative embodiments. Other substitutions, modifications, changes andomissions may also be made in the design, operating conditions andarrangement of the various exemplary embodiments without departing fromthe scope of the present invention. Unless otherwise expressly stated,it is in no way intended that any method set forth herein be construedas requiring that its steps be performed in a specific order.Accordingly, where a method claim does not actually recite an order tobe followed by its steps or it is not otherwise specifically stated inthe claims or descriptions that the steps are to be limited to aspecific order, it is in no way intended that any particular order beinferred. In addition, as used herein the article “a” is intendedinclude one or more than one component or element, and is not intendedto be construed as meaning only one.

For purposes of this disclosure, the term “coupled” means the joining oftwo components directly or indirectly to one another. Such joining maybe stationary in nature or movable in nature. Such joining may beachieved with the two members and any additional intermediate membersbeing integrally formed as a single unitary body with one another, orwith the two members and any additional member being attached to oneanother. Such joining may be permanent in nature or alternatively may beremovable or releasable in nature. Various embodiments of the inventionrelate to any combination of any of the features, and any suchcombination of features may be claimed in this or future applications.Any of the features, elements, or components of any of the exemplaryembodiments discussed above may be utilized alone or in combination withany of the features, elements, or components of any of the otherembodiments discussed above.

In various exemplary embodiments, the relative dimensions, includingangles, lengths and radii, as shown in the Figures are to scale. Actualmeasurements of the Figures will disclose relative dimensions, anglesand proportions of the various exemplary embodiments. Various exemplaryembodiments extend to various ranges around the absolute and relativedimensions, angles and proportions that may be determined from theFigures. Various exemplary embodiments include any combination of one ormore relative dimensions or angles that may be determined from theFigures. Further, actual dimensions not expressly set out in thisdescription can be determined by using the ratios of dimensions measuredin the Figures in combination with the express dimensions set out inthis description. In addition, in various embodiments, the presentdisclosure extends to a variety of ranges (e.g., plus or minus 30%, 20%,or 10%) around any of the absolute or relative dimensions disclosedherein or determinable from the Figures.

What is claimed is:
 1. A level comprising: a level body comprising abase surface; at least one level indicator located within the levelbody; a cavity located in the level body defining an opening along thebase surface; a magnetic circuit coupled to the level body within thecavity, the magnetic circuit comprising: a pair of metallic sleeves; anda permanent magnet located between opposing inner surfaces of the pairof metallic sleeves; wherein each of the metallic sleeves having acorner located between an angled surface and an inner vertical surface;wherein the each of the metallic sleeves has a width and the permanentmagnet has a width; wherein the width of each of the metallic sleeves isgreater than the width of the permanent magnet.
 2. The level of claim 1,the level body formed from a first material and the pair of metallicsleeves formed from a second material.
 3. The level of claim 2, whereinthe second material is different from the first material.
 4. The levelof claim 2, wherein the second material has a magnetic reluctance thatis less than a magnetic reluctance of the first material.
 5. The levelof claim 1, wherein the magnetic circuit has a length and wherein thelength of the magnetic circuit is greater than the width of the pair ofmetallic sleeves combined with the width of the permanent magnet.
 6. Thelevel of claim 1, further including a groove formed in the base surfaceand extending in a longitudinal direction along an entire length of thebase surface, the groove including a pair of longitudinally-extendingsurfaces positioned at an angle relative to a horizontal axis.
 7. Thelevel of claim 6, wherein the angled surface of each metallic sleeveangles inwards towards the permanent magnet at an angle matching theangle of the pair of longitudinally-extending surfaces of the groove. 8.The level of claim 7, wherein the angled surface of each metallic sleevedefines a plane at an angled position relative to the base surface.
 9. Alevel comprising: a level body formed from a first metallic material,the level body comprising a base surface configured to engage aworkpiece; at least one level indicator located within the level body; agroove extending in a longitudinal direction formed in the base surface;and a first magnetic circuit and a second magnetic circuit locatedwithin the groove, the first magnetic circuit comprising: a first pairof metallic sleeves formed from a second metallic material; and a firstpermanent magnet located between opposing inner surfaces of the firstpair of metallic sleeves; the second magnetic circuit comprising: asecond pair of metallic sleeves formed from the second metallicmaterial; and a second permanent magnet located between opposing innersurfaces of the second pair of metallic sleeves.
 10. The level of claim9, wherein the level indicator is a rotating level vial mounted suchthat the level vial is positionable at different angles relative to thebase surface.
 11. The level of claim 10, further including a lock thatengages the rotating level vial such that the rotating level vial can befixed in a selected position.
 12. The level of claim 11, wherein thelock is a friction lock positioned at an end of the level.
 13. The levelof claim 12, wherein the second magnetic circuit is located along thebase surface at least in part between the rotating level vial and theend of the level that includes the lock.
 14. The level of claim 9, thelevel further including a horizontal level vial positioned in a paralleldirection relative to the base surface and a vertical level vialpositioned in a perpendicular direction relative to the base surface.15. The level of claim 14, wherein the first magnetic circuit is locatedalong an axis perpendicular to the base surface below at least a portionof the horizontal level vial.
 16. The level of claim 9, wherein thesecond metallic material is a ferromagnetic material and is differentfrom the first metallic material.
 17. A level comprising: a level bodycomprising a base surface configured to engage a workpiece; at least onelevel indicator located within the level body; a cavity located in thelevel body defining an opening along the base surface; and a magneticcircuit located within the cavity, the magnetic circuit comprising: apermanent magnet including a first outer lateral surface and a secondouter lateral surface; a first sleeve located on a first side of thepermanent magnet; and a second sleeve positioned on a second side of thepermanent magnet opposite from the first sleeve.
 18. The level of claim17, the permanent magnet having a tapered shape and the first and secondsleeves having inner surfaces with a corresponding opposite taperedshape such that the permanent magnet and first and second sleevesinterlock.
 19. The level of claim 17, wherein the first and second outerlateral surfaces of the permanent magnet each include a first sectionangled inwards toward an upper surface of the permanent magnet and asecond section angled inwards toward a lower surface of the permanentmagnet.
 20. The level of claim 19, wherein a width of the permanentmagnet at the upper surface and the lower surface is less than a widthat a center of the permanent magnet.